1. Field of the Invention
This invention relates to the solution polymerization of a halogenated aromatic polyester.
2. Description of the Prior Art
Halogenated aromatic polyesters may be prepared by solution polymerization of a halogenated aromatic bisphenol and a diacid halide. In accordance with typical solution polymerization procedures of the prior art, the reactants are present in a common solvent which also serves as a solvent for the polymer under the conditions of condensation. The bisphenol and the diacid halide are dissolved in separate portions of the chosen solvent. A catalyst or acid acceptor is added and the solutions are combined with agitation. Control of the molecular weight of the resulting polymer has heretofore been achieved by utilizing specific amounts of reactants in accordance with exact stoichiometric calculations. Once the required amount of reactants have been determined in this manner they are rapidly combined and allowed to polymerize until a maximum inherent viscosity is achieved. Although this method is capable of achieving a polymer having a predetermined molecular weight such a procedure possesses many disadvantages when carried out on a commercial scale. For example, commercial starting materials are non-uniform and they vary from batch to batch. Moreover, the starting materials often contain impurities which, although not adversely affecting the resultant polymer, require correction in the above described calculations to account for their presence. Thus, a non-uniform and impure starting material often leads to weighing errors which in turn give rise to deviations from the predetermined molecular weight in the final polymer product.
The presently claimed process avoids the necessity for careful and costly weighing and analysis procedures necessitated by the raw materials used to prepare the polymer and allows for the production of a uniform product of a predetermined molecular weight.
Typical solution polymerization procedures for preparing polyesters are outlined in U.S. Pat. Nos. 3,234,167 and 3,309,334.
It is therefore an object of the presently claimed invention to provide an improved and relatively inexpensive process for the preparation of high molecular weight halogenated aromatic polyesters of the type disclosed herein.
It is a further object of the present invention to provide a process for achieving a halogenated aromatic polyester of a predetermined molecular weight.
It is a still further object of the present invention to provide a process for preparing a halogenated aromatic polyester having a reproducible molecular weight.
It is a further object of the present invention to provide a continuous process for controlling the molecular weight of a halogenated aromatic polyester.
These and other objects as well as the scope, nature and utilization of the invention will be apparent to those skilled in the art from the following description and appended claims.